John A. Dahlgren

John Adolphus Bernard Dahlgren (13 November 1809-12 July 1870) was a US Navy Rear Admiral during the American Civil War, most notable for his invention of the Dahlgren gun.

Biography
John Adolphus Bernard Dahlgren was born in Philadelphia, Pennsylvania in 1809, the son of the Swedish consul and his American wife; he was the brother of Charles G. Dahlgren and the father of Ulric Dahlgren. He joined the US Navy in 1826 as a midshipman and was assigned to the Washington Navy Yard in 1847, inventing the cast-iron, muzzle-loading Dahlgren gun in 1860. When the American Civil War broke out, he became commander of the Washington Navy Yard and was promoted to Rear Admiral in February 1863 and given command of the South Atlantic Blockading Squadron. In 1864, he helped William T. Sherman capture Savannah, Georgia during his March to the Sea. In 1867, after the war's end, he took command of the South Pacific Squadron, and he was relieved in 1869, returning to command the Washington Navy Yard until his death in 1870.